Cautionary note: the copying machine must be able to reproduce the highest frequency, on the subject tape, multiplied by the dubbing speed. Thus to copy 20Hz-15kHz at 2x speed the dubbing machine must have 40Hz to 30kHz capability. This is beyond the performance of even high-end consumer decks. However, if you only wish to copy speech any deck that does 2x transfer will probably suffice.

e.g. Pyle Pro PT-659DU Dual Stereo Cassette Deck w/Tape USB PT659DU This one does the digital conversion. Alesis has one for twice the price.

Cheers, Marshall.